Continued support is requested for five predoctoral trainees per year for five years for an interdepartmental training program in the molecular genetics of basic cell functions. The emphasis is on rigorous training using the power of genetic analysis to study basic cell processes, such as chromosome replication and segregation, regulation of gene expression, cellular differentiation, and host-parasite interactions. This training program has strongly benefited from continuous support from NIGMS since 1975. Supported students are almost exclusively in their first year, allowing them to have a broad exposure to the role of genetics as a science in itself and as a tool for solving important biological problems. The training faculty, from the Departments of Molecular Biology and Microbiology, Biochemistry, Pathology, and Medicine, is highly interactive and dedicated to close, joint supervision and mentoring of graduate students. Past trainees include leading researchers in academia and industry. The training program is administered by the Graduate Program in Molecular Microbiology. Starting with a pool of 80-115 applicants, the graduate program annually admits 5-7 new students, most or all of whom are eligible for training grant support. The program has been successful in attracting a significant number of students from underrepresented groups (including 8 of the 32 current students), nearly all of whom have been supported by this training grant. Nearly all graduates of the program have obtained high-quality postdoctoral appointments and are still active as researchers, as teachers, or in allied fields. Entering students take required courses in Genetics, Biochemistry and Microbiology and pursue 9-week rotation projects in four different laboratories. At the end of the first academic year, the choose a thesis supervisor and begin thesis research. In the second and third years, the students complete their coursework and prepare a research proposal (unrelated to the thesis topic) as a qualifying examination. All students are required to complete a seminar course in scientific ethics.